There is a lot of strange things about this bombing. Check out the thread about the giant crater outside the hotel.
Witnessed by many, including a PPP MNA and his friends, a US embassy truckload of steel boxes was unloaded and shifted inside the Marriott Hotel on the same night when Admiral Mike Mullen met Prime Minister Yousuf Raza Gilani and others in Islamabad. Both the main gates (the entrance and the exit) of the hotel were closed while no one except the US Marines were either allowed to go near the truck or get the steel boxes unloaded or shift them inside the hotel. These steel boxes were not passed through the scanners installed at the entrance of the hotel lobby and were reportedly shifted to the fourth and fifth floors of the Marriott.
A wounded hotel security official said a truck had been stopped at the hotel's security barrier and two small explosions had gone off minutes before the main blast.
Clemens Steinkanp, a German who was slightly wounded, said hotel security men had warned guests to move to the back of the building shortly before the bomb went off.
"Nothing happened for five minutes ... but then there was a huge blast," he said.
A small blast in the lobby in October 2004 killed one person, and while the government publicly blamed an electrical circuit, security officials privately admitted it was a bomb hidden in a laptop.
A suicide bomber then blew himself up just outside the hotel in January 2007, killing a security guard who stopped him from ducking into a side entrance leading towards the Marriott's basement nightclub.
The Marriott made a huge effort to boost security after the latter attack.
It erected massive metal and concrete vehicle barriers outside the hotel and increased checking on all cars entering the compound. The lobby was also extended to include extra body scanners and X-ray machines for bags.